Heavy Algal Blooms Research Articles

High abundances of the nuisance raphidophyte Gonyostomum semen in brown water lakes are associated with high concentrations of iron

Algal blooms occur frequently in lakes and oceans and the causes and consequences of those are often studied. In this study, we focus on a less well known type of algal bloom by the freshwater raphidophyte Gonyostomum semen. This species’ abundance and occurrence is increasing, especially in brown water lakes, the most abundant lake type in the boreal zone. The aim of the study was to investigate which environmental factors are associated with G. semen by statistical evaluation of field data of 95 Swedish lakes over five years. Although we found G. semen to be associated with dark waters it was, contrary to our expectations, mainly high concentrations of iron, and only to a lesser extent high TOC (total organic carbon) concentrations, that were associated with blooms of G. semen. In addition, high phosphorus concentrations and low pH also appear to facilitate G. semen blooms. We suggest that browning of lakes caused by increased iron concentrations may decrease net heterotrophy by fostering heavy algal blooms, i.e. the opposite to commonly assumed effects of increased DOM (dissolved organic matter).

Characterization of blooming algae and bloom-associated changes in the water quality parameters of traditional pokkali cum prawn fields along the South West coast of India.

In tropical shrimp farms, especially in traditional pokkali shrimp ponds, poor water quality management can lead to serious threats like heavy algal blooms and frequent disease outbreaks. An investigation regarding the frequent disease outbreaks in selected pokkali shrimp pond adjoining the Cochin backwaters has been conducted. Water quality parameters were analyzed during the study period. Results indicate a considerable fluctuation in the concentration of dissolved oxygen (DO) in the study in the shrimp farm where the algal bloom was observed. Poor water exchange along with nutrient loading from adjacent housing areas resulted in heavy algal bloom in the pond which led to hypoxic conditions in early morning and supersaturation of DO in the afternoon. It also led to considerably high alkaline pH. High levels of total ammonia nitrogen (TAN) were recorded in the sampling sites. Heavy algal bloom was observed throughout the study period in the selected pond especially in the summer. Anabaenopsis elenkinii and Merismopedia elagans which were the dominant species from the culture pond caused the bloom. Characterization and percentage distribution of bacteria present in the water and those associated with the algal blooms were carried out. The algae were found to support greater diversity of bacteria when compared to water. Pathogenic species like Aeromonas hydrophila and Vibrio parahaemolyticus were encountered in the study. Experimental challenge studies using Artemia as a model showed that the V. parahaemolyticus isolates were highly pathogenic. Hence, this study reveals how algal growth supports opportunistic pathogens in great diverse in a shrimp pond and causes frequent disease outbreaks under favourable conditions.

An assessment of water quality and pollution in Puranawella fishery harbour, Dewinuwara, Sri Lanka.

Fishery harbours in Sri Lanka have been facing severe pollution problems since recent past. However, a systematic monitoring of the pollutant load has not been done. This study was carried out at Puranawella harbour, located in the southern coast of Sri Lanka, with the objective of assessing the severity of the pollution level. Investigation was carried out at seven sampling stations at three week intervals during the period from December 2010 to February 2011. Spatial and seasonal variations of physico-chemical parameters and phytoplankton abundances were examined together with bacteriological analyses. Among the characteristics studied, significant differences between sampling stations were observed for water transparency, chemical oxygen demand, orthophosphate, nitrite, oil and grease content of surface and bottom water as well as Cu and Pb in water and sediment. Water temperature, pH, salinity, total suspended solids, total dissolved solids, dissolved oxygen, biological oxygen demand, Pb in sediment and phytoplankton abundance showed significant variations among sampling months. Harbour water was characterized significantly by poor transparency (0.35m - 4.00m) and high amount of total suspended solids (0.015 - 0.072 gl-1), total dissolved solids (6.98 - 43.79 gl-1), high biological oxygen demand (0.44 - 8.08 mgl-1), high chemical oxygen demand (0.78 - 23.4 mgl-1), high orthophosphate (0.008 - 1.58 mgl-1) and a high proportion of Nitrite (0.02 - 1.83 mgl-1) indicating a severe eutrophication. Biological oxygen demand close to harbor jetty was 4.46 mgl-1, which exceeded the recommended quality standard. Orthophosphate in surface waters exceeded the limit 0.015 mgl-1, amount necessary for the establishment of heavy algal blooms. Oil and grease content of surface (9 - 82 mgl-1) and bottom water layers (22 - 241 mgl-1) inside the harbour also exceeded the recommended value of 10 mgl-1. The concentration of Cu and Pb in water exceeded the standard value of 0.5 mgl-1. MPN value of total coliforms (per 100 ml) ranged between 5 and 2400, which also exceeded the recommended standards. The phytoplankton density ranged between 16356 and 62500 cells/m3. Results of this study revealed that the water quality of the arbour has been degraded and harbour is subjected to severe oil pollution, organic pollution and microbial contamination. Since this study was carried for only 3 months, a yearlong study is required to come to stronger conclusions.DOI: http://dx.doi.org/10.4038/jur.v1i1.6157 Journal of the University of Ruhuna 2013 1(1): 23-30

Comparison of mercury speciation and distribution in the water column and sediments between the algal type zone and the macrophytic type zone in a hypereutrophic lake (Dianchi Lake) in Southwestern China

During a heavy algal bloom in 2009, we collected lake water, surface sediment, sediment cores and porewater samples from Dianchi Lake to investigate the effect of eutrophication and different aquatic habitats (algal and macrophytic) on mercury (Hg) distribution and speciation in hypereutrophic lake. The total Hg (THg) concentration in the sediment and lake water was substantially elevated compared to uncontaminated lakes and reservoirs. The spatial distribution of THg pointed to waste water discharged from Kunming City as the dominant source of Hg in Dianchi Lake. Despite the high concentration of THg, the concentration of methyl mercury (MeHg) was relatively low compared to other deep water lakes and reservoirs, and the ratio of MeHg/THg was generally lower than 1% in lake water and sediments, implying the low potential of Hg methylation. No significant relationship was found between the total organic carbon (TOC) and MeHg in either surface sediment or sediment cores. This result is different from previous conclusions that an increase of organic material load in sediment can enhance the potential of Hg methylation in sediments. A significant relationship between the total S and MeHg in the two cores indicated that sulfur played an important role in Hg methylation. However, because of similar concentrations of MeHg and distinct differences in the S concentration in the two cores, the total S should not be a limiting factor for Hg methylation in sediment. The most important limiting factors controlling Hg methylation were high pH and Eh induced by heavy algal blooms and shallow water depth in Dianchi Lake because Hg methylation will be inhibited and the demethylation of MeHg may be accelerated under alkaline and oxic conditions.

都市公園池の富栄養化特性とクロロフィルａとの関係

The water quality of city park ponds must be kept at certain levels because such ponds are important facilities for the comfortable life of citizens, and hence must be improved if heavy algal blooms occur frequently. Nitrogen, phosphorus, and chlorophyll concentrations were measured from 1999 to 2003 for four park ponds in Osaka city to investigate eutrophication and its causes. The means TN, TP and Chl.a concentrations ranges were 0.89-5.4 mg-N · l-1, 0.12-0.67 mg-P · l-1, and 24-310 μg · l-1 respectively. In the comparison of water quality with those of irrigation ponds and other park ponds, three of the four ponds showed intermediate levels, and the remaining one showed much progressed levels. Treated sewage water, effluent water from a landfill site, and water from a pumping well accelerated the trophic state of ponds easily. A pond where a low Chl.a concentration but with high TN and TP concentrations existed. Thus, it was surmised that treated sewage water flowing into a pond indirectly influences pond water quality. Also, there was a park pond that decreases its TN concentration markedly in summer, and denitrification in the emergent plant zone was suspected. Since such characteristics may also contribute to water quality improvement, further studies are required.

Occurrence of toxic blue‐green algae in the Kucukcekmece lagoon (Istanbul, Turkey)

The concentration of microcystin (MC) in the Kucukcekmece Lagoon, Istanbul, Turkey, and the physicochemical and biological parameters of water quality were investigated from October 2000 to June 2003. Water samples were collected from surface waters at three sites. Most bloom samples were dominated by Microcystis aeruginosa. The major microcystin variants detected by HPLC-PDA were microcystin-YR and microcystin-LR. Microcystin concentration increased dramatically from early summer to early autumn and thereafter tended to decrease. The toxin concentration found in the filtered samples from surface waters varied between 0.06 and 24.2 microg L(-1) microcystin-LR equivalents. Each year extensive fish mortality was recorded between mid-June and early October, coinciding with heavy algal blooms. A comparison of the conditions associated with cyanotoxin episodes in 2000, 2001, and 2002 showed that the microcystin increase was related to temperature, high concentration of dissolved nutrients, high light intensity (PAR). The highest MC concentrations were recorded at temperatures between 24 degrees C and 28.5 degrees C. Field data showed that the highest MC concentration (>3 microg L(-1)) and the highest cyanobacterial biomass (>30 mg L(-1)) corresponded to a total nitrogen:total phosphorus ratio greater than 7:1. The highest concentrations of M. aeruginosa biomass (173 mg L(-1)) and MC (24.2 microg L(-1) MC-LR equiv.) and the highest salinity (8.8%) were measured concurrently in the lagoon. To our knowledge, this is the first evidence of cyanobacterial toxins in the Kucukcekmece Lagoon.

Anatoxin-a toxin in the cyanobacterium Planktothrix rubescens from a fishing pond in northern Italy.

A heavy algal bloom occurring in a fishing pond in northern Italy full of Salmo trutta was examined for algae taxonomy and toxic production. The dominant algal species (98%) was identified as the cyanobacterium Planktothrix rubescens (D.C. ex GOMONT) Komarek Anagnostidis, based on morphological examination, and it was revealed to be toxic in mouse and Vibrio fischeri bioassays. The toxin was identified as anatoxin-a using high-performance liquid chromatography and confirmed using liquid chromatography-mass spectrometry (LC-MS). The mouse bioassay gave signs of poisoning, as previously reported for anatoxin-a. The LC-MS confirmed the presence of an anatoxin-a peak at m/z 166 (M+H+). The content of toxin in the field population was estimated at 12.13 microg/g of fresh cells. The bloom was sustained by the very high N/P ratio in the water. This is the first report in Italy of an anatoxin-a-producing Planktothrix rubescens population.

Eutrophication Of The Shallow Szczecin Lagoon (Baltic Sea): Modelling,Management And The Impact Of Weather

The Oder estuary, especially the large, shallow Szczecin (Oder) Lagoon (687 km2, average depth 3.8 m) suffers from severe and ongoing eutrophication due to heavy loads, mainly by the Oder river. Poor water quality nowadays is a main obstacle for further touristic development around the lagoon. Long-term nutrient concentrations show a high interannual variability and a decline during recent years. Using a simple eutrophication box model and comparing dry, warm years (1989-1991) with colder, wet years (1986-1988) we analyse the impact of interannual and short-term weather conditions on the eutrophication process. Internal nutrient cycling processes in the lagoon are mainly driven by shortterm weather conditions. During rare and short calm summer periods a stratification and oxygen depletion above the sediment is likely. Coarse model-based estimations indicate an anoxic P-release from sediments of up to 10 μmol P md or up to 400-600 t P for the entire lagoon. These situations are restricted to several days and occur only in a few years. Wind with a daily average velocity above 2-3 m/s cause mixing and put an end to anoxic P-release. Compared to a monthly summer load of 100-150 t P by the Oder river, internal eutrophication in the lagoon is important, but has no pronounced effect on biology. In wet years the P and N load with the Oder river can be up to twice as high compared to dry years. Discharge and load by rivers control the nutrient dynamic in the Szczecin Lagoon, to a high degree. The observed reduction in nutrient concentrations in early 90’s is an effect of the warm, dry years and cannot be attributed to anthropogenic nutrient load reductions. Management implications are discussed. 1 Problems and management challenges in the Oder estuary The large Oder-catchments is located at the German-Polish border. With a surface area of 120,000 km and a population of about 13 Mio inhabitants it is responsible for the heavy nitrogen and phosphorous load of the Oder river. In recent years, about 63,000 t total N/a and 3,500 t total P/a were transported with the Oder towards the Baltic Sea. The river therefore is the most important source of eutrophication and pollution for the south-western Baltic Sea. The respective coastal zones, especially the Szczecin (Oder) Lagoon, suffer from severe eutrophication, heavy algal blooms of potentially toxic species, high water turbidity and even hygienic quality problems [1]. The Szczecin Lagoon is a key element of the Oder river estuary. It is a large (687 km2) and shallow (average depth 3.8 m) coastal flow lake. The lagoon consists of two main parts Kleines Haff on the German side and Wielki Zalew located on Polish territory (Fig. 1). The Wielki Zalew comprises about 60 % of the lagoon area and volume. A theoretical water exchange time of the entire water body is about 2 months, but its western part (Kleines Haff) receives only between 10 % and 20 % of the Oder water [2]. Germany Sweden Finland Poland Germany Poland Dziwna

The macrobenthos of the north sea

The potential threat to the North Sea ecosystem due to pollution by organic and chemical wastes, has directed attention to the benthic assemblages in the sea. Because these assemblages comprise a wide range of ecological groups and species, many of which have a life span surpassing one year, they integrate effects of pollution over long periods of time. Knowledge on the spatial distribution of different types of assemblages allows assessment of the extension of possible effects over large areas. Analysis of the macrobenthos collected in the Dutch, German and Danish sectors of the North Sea during the synoptical ICES NORTH SEA BENTHOS SURVEY, showed that the samples from this area can be grouped into four clusters on the basis of macrofaunal similarity. Because the geographical distribution of the clusters correlated well with sediment characteristics and depth, for convenience the clusters can be described as shallow coarse- (medium-)sand, shallow fine-sand, shallow muddy-sand and deep muddy-sand. These four clusters differ not only with respect to species composition, diversity and biomass, but also with respect to their consumption and production of organic material. The differences between the structure and functioning of the clusters are interpreted in the light of local differences in the production and deposition of organic material and physical stress on the bottom. Because of the paucity of long-term series of observations, the important question as to whether the present situation shows signs of eutrophication cannot be addressed for the entire investigated area. In the German Bight, where nutrient levels have increased during the past decades and heavy algal blooms have been reported, the macrobenthic communities have not shown a major change. Even after mass mortality among benthic animals due to oxygen deficiency following the breakdown of algal blooms, the benthic community rapidly regained its former structure. This is explained by the dominance of physical factors in shaping the community of this shallow sand habitat. In the more protected muddy-sand habitats, on the other hand, similar events may lead to more permanent changes due to the importance of biological interactions. The available data from studies on the effects of single-point organic inputs on macrobenthic species can be used to predict the sort of changes that would take place in the case of large-scale eutrophication and can help to determine whether this is taking place.

Nutrients and Algal Growth in an Impounded River, Consequences for its Oxygen Balance and Nutrient Control Strategy

A series of impoundments occur on the final 46 km stretch of the Ruhr river where phosphorus, nitrogen, and organic carbon are present abundantly, causing several heavy algal blooms during the year. This is detrimental for the treatment capacity of the water works. Also, an oxygen shortage is always recorded in the river after algal decay at low flows, thus requiring artificial aeration. By balancing all oxygen supply and consumption it is shown that about 2/3 of the oxygen demand is due to algal decomposition. When evaluating the water quality data of the past 30 years and by conducting special laboratory tests, results show that phosphates initiate algal growth. Therefore, a phosphate model has been developed for the river which predicts the phosphate content for 1988 and 1998. It is expected that by reduction of this phosphate content maximum algal growth can be cut by about 50 %.

Summerkill Risk in Prairie Ponds and Possibilities of its Prediction

Summer fish kills in shallow, landlocked ponds of the Erickson–Elphinstone area, southwestern Manitoba, were caused by collapses of heavy algal blooms, mostly Alphanizomenon flos-aquae, and subsequent oxygen depletion. Kills occurred only in ponds that were in the specific conductance range of 800–2000 μmho/cm and where chlorophyll a concentrations exceeded 100 μg/liter. A practical rating system for assessment of summerkill risk was suggested. Correlations between various parameters from 51 ponds were computed; the best correlation (r = 0.866; P = >0.99) was found between the late-winter concentration of ammonia nitrogen and the maximum concentration of chlorophyll a in the following summer. Two summerkill prediction systems were proposed, based on ammonia, dissolved oxygen, and Secchi disc transparency, enabling the prediction of summerkill risk 9 or 3 mo prior to stocking of the fish.

Problems of the Optimum Catch in Small Whitefish Lakes

T HE WHITEFISH fishery of the Canadian prairies is pursued in hundreds of widely scattered lakes, most of which are small and shallow, but highly productive. The whitefish, Coregonus clupeaformis Mitchill, thrives in them, despite the fact that they warm to the bottom every summer and produce heavy algal blooms. In the province of Alberta, these lakes range in size from ten to over four hundred square miles in area and each produces from fifty thousand to over half a million pounds of whitefish per year. The annual catch of whitefish from these lakes is governed by the quota system; each lake has a limit set for each fishing season; when the limit has been taken, the local fish inspector closes the lake. If, at the time the lake is closed, the fishing is still good and the season not advanced, it is common practice to grant extensions and re-open lakes for a further limit. From time to time, one or another of these lakes fails to produce whitefish of commercial size when the fishing season opens. The lake is declared to be fished out and is closed for one or more years until tests show it to be yielding good fish again. Heavy plantings of eyed eggs or fry are made to help the restoration. These trial and error tactics have worked fairly well, and, over a period of twenty-five years, administrators have arrived at a fair estimate of the sustained annual yield of each lake. However, this type of administration does not provide the answers to several important questions. First, it is not possible to predict when a particular fishery may collapse, since it cannot be shown that -any particular collapse is due to overfishing. Second, the optimum catches-the reaching of a proper balance between recruitment and mortality-are unknown and probably differ from the actual catches. Third, the effect, if any, of the plantings of eyed eggs or fry is not known.

A Sudden Mortality of Fishes Accompanying a Supersaturation of Oxygen in Lake Waubesa, Wisconsin

A heavy loss of fish occurred during April 1940, in the south end of Lake Waubesa, Wisconsin, and in the Yahara River below the lake. The fish affected were mainly black crappies, although bluegills, northern pike, yellow pikeperch, common suckers, and carp, were killed to a lesser extent. A heavy algal bloom composed principally of Chlamydomonas was concentrated in the area of fish loss and was accompanied by an extremely high (30–32 p.p.m.) oxygen content in the surface water. Characteristic lesions were present in the fish and consisted primarily of gas emboli in the gill capillaries and gas bubbles in the subcutaneous tissues. Death of the fish was attributed to the blocking of the circulation through the gills by the gas bubbles with consequent respiratory failure. A suggestion is made that oxygen was the gas forming the bubbles.